The invention relates to in vitro extraction of intracellular material while maintaining cell viability.
Living cells are implanted with new genes to form living factories producing specific molecules such as insulin, interferons, human growth hormone, etc. Unfortunately, even when such a "factory cell" produces large amounts of the desired molecules, most of them remain inside the membrane of the cell when it is alive. A variety of techniques have been developed to "harvest" these desired molecules.
The prior art teaches in vitro extraction of intracellular material by means of physical and/or chemical destruction of the cellular membrane, thereby releasing the cellular contents into the suspension medium, thereafter to be retrieved by conventional filtering techniques. Notwithstanding the substantial quantity of intracellular molecules obtained thereby, the cells are no longer viable biological entities subsequent to such treatment, and no additional molecular production is possible.
Alternatively, the prior art teaches the use of pulsed electric fields to create pores on the membranes of cells suspended in high-resistivity solutions through which intracellular material of limited dimension might diffuse, if given sufficient time. Unfortunately, the self-healing nature of cellular membranes rapidly eliminates membrane poration, thereby limiting the amount of time available for diffusion and, hence, limiting the quantity of intracellular material removed by this method. Moreover, the prior art fails to adequately separate the subject cells from each other prior to membrane poration, thereby promoting intercellular fusion rather than intracellular extraction.